Conventionally, lossy coding and lossless coding are separately developing. That is, most lossless compression techniques focus on lossless compression functions, while lossy coding methods are aimed at enhancing compression efficiency regardless of lossless compression.
Traditional technology, such as Free Lossless Audio Codec (FLAC) or Shorten, performs lossless coding as follows. An input signal is subjected to a prediction encoding module to form a residual signal via, and the residual signal is subjected to a “Residual Handing” module, such as a differential operation, in order to reduce a dynamic range thereof, so that a residual signal with a reduced dynamic range is output. The residual signal is expressed as a bitstream by entropy coding as a lossless compression technique and transmitted. In most lossless compression techniques, the residual signal is compressed and encoded through one entropy coding block. FLAC employs Rice coding, while Shorten uses Huffman coding.